1. Field of the Invention
The present invention relates to an apparatus and method of assembling a semiconductor device and positioning and fixing a semiconductor element to a substrate. The present invention also relates to a semiconductor device fabricated by such a method and apparatus.
2. Description of the Related Art
Many semiconductor devices have been designed in which a semiconductor element such as a photodiode or a laser diode is fixed to a substrate. To obtain such a semiconductor device, it is necessary to position and fix the semiconductor element at a certain position relative to the substrate. In the conventional method of assembling a semiconductor device, positioning marks are provided in the substrate, the semiconductor element is moved onto the substrate, and the semiconductor element is positioned relative to the substrate by moving semiconductor element in such a manner that the bottom of a side of the semiconductor element is overlaid on the positioning marks.
Such a conventional method, however, has the drawback that, when the semiconductor element comes near to a target position, the positioning marks are hidden by the semiconductor element and cannot be seen, so it is difficult to achieve the positioning of the semiconductor element with good accuracy in a short time. If the positioning mark is displaced to a position in front of the target position of the semiconductor element, the positioning mark can be easily seen but the positioning of the semiconductor element cannot be accurately attained.
Moreover, the bottom surface of the semiconductor element is not always in intimate contact with the surface of the substrate, and it is necessary to perform the positioning of the semiconductor element in a state where there is a gap between the bottom surface of the semiconductor element and the surface of the substrate. Thus, when the positioning of the semiconductor element is performed while observing the semiconductor element and the substrate, both the bottom surface of the semiconductor element and the surface of the substrate are not in focus, so it is difficult to position the semiconductor element by simultaneously observing both the substrate and the semiconductor element. Furthermore, it is difficult to quickly move the semiconductor element to a target position, so it is not possible to automatically position the semiconductor elements.